The main goals of holding a meeting on proline metabolism is to cover a diverse breadth of topics related to human health and disease and to increase the network of researchers in the field. Proline has multifaceted biological and biochemical roles in a variety of organisms from bacteria to mammals. The unique roles of proline metabolism in various organisms include osmolyte protection, protein chaperoning, nitrogen and carbon utilization, abiotic/biotic stress response, oxidative stress protection, and nutrient adaptation and survival. In humans, proline metabolism is recognized as having an important impact on bioenergetics, cellular redox control, apoptosis, cancer, schizophrenia, and connective tissue development. Inborn errors in proline metabolic genes are manifested in neurological dysfunctions such as schizophrenia, increased incidence of seizures, connective tissue diseases, premature aging, and osteopenia. The inaugural proline meeting was held in 2004 at the National Cancer Institute and a second conference was held in 2007. Due to the enthusiasm from previous meetings, a third symposium on Proline Metabolism is being organized that will cover a wide array of topics that are of interest to NIH. The topics that will be discussed include: (a) p53 and proline signaling pathways in cancer;(b) risk and protective functional polymorphisms of proline dehydrogenase in schizophrenia;(c) proline neurotoxicity;(d) disease causing mutations in pyrroline-5-carboxylate reductase and connective tissue disorders;(e) proline metabolic cycling and oxidative stress;(f) nutrient stress response;(g) trypanosomes, adaptation and survival;(h) proline transport and utilization in pathogenesis;(i) structure and function of proline metabolic enzymes;(j) detoxification of organophosphorus nerve agents;(k) regulatory mechanisms of proline metabolic gene expression;and (l) substrate channeling in the proline oxidation pathway. The conference program has speakers from diverse scientific disciplines, which will provide an excellent training experience for younger scientists. The planned activities of the conference will facilitate interactions between junior and more established scientists. This conference provides the only opportunity for the international community of proline metabolism researchers to gather to discuss new results and the impact of their research on human health and disease. PUBLIC HEALTH RELEVANCE: The amino acid proline has multifaceted roles in organisms ranging from bacteria to humans. Research into proline metabolism is helping our understanding of cancer preventing mechanisms, how disease carrying parasites (e.g., Trypanosoma brucei, African sleeping sickness) and pathogenic bacteria (e.g., Staphylococcus aureus) adapt and survive, mitochondrial energetic processes, connective tissue and skin disorders, and neuropsychiatric dysfunctions such as schizophrenia. This conference on proline metabolism will enable researchers from around the world to discuss their latest results, initiate collaborations and develop new strategies for improving human health and combating infectious diseases.